Vehicle air-brakes systems require a supply of pressurized air. It is known in the art to provide a valve means in air-brake systems to control air flow direction and timing through the system, e.g., U.S. Pat. No. 4,714,297. For additional safety, a secondary pressurized air supply may be provided. Generally, a secondary pressurized air supply comprising a second air tank may provide a back-up air supply for the system. It is also known in the art to provide an exterior passageway extending between the supply tank and secondary air tank such that both the supply and secondary tanks may be pressurized through a single inlet. The inlet receiving pressurized air from an air pressure source is in fluid communication with the supply chamber and a check valve is usually disposed in the exterior passageway to provide one-way fluid flow from the supply chamber to the secondary chamber to thereby pressurize the secondary chamber. While such systems may provide the desired function of pressurizing the secondary chamber, the exterior passageway and/or check valve disposed therein are susceptible to physical damage. Such physical damage may in turn prevent the secondary chamber from being properly charged and thereby defeat the purpose of providing the desired back-up air supply to the air-brake system. Moreover, an exterior passageway requires manufacturing additional parts and thus adds to the cost of the system.
The use of check valves, as indicated above, in fluid flow applications is well known. For example, U.S. Pat. No. 28,722 discloses a specific type of check valve which may be used in a vessel having a flexible diaphragm separating a higher pressure region from a lower pressure region. Such a check valve, however, could not be used in a vessel having a rigid wall separating two chambers.
It is desirable to provide a system for simultaneously charging both a supply and a secondary chamber of a multi-compartment air-brake reservoir system which is relatively easy and inexpensive to manufacture and not susceptible to physical deformation from externally applied forces.